Portable radio transmitters have been provided which are adapted to be held in the hand of the user. Radio transmitters which have been available have had limited power and have been objectionably large. In prior units, microstrip transmission lines have been used for impedance matching elements, but in the very high frequency range such transmission lines are objectionably large and have low efficiency. For operation at relatively high power levels, the microstrip transmission lines have objectionably high insertion loss and if there is some unbalance of the lines, the loss significantly increases. Also, it has been difficult to tune the prior circuits after assembly of the components thereon.
Although RF amplifier stages have been provided as modules, it has been necessary to mount such modules to a chassis in a manner which provides an adequate ground for the circuit and heat sinking for the active elements thereof. A further problem results in providing the power amplifier in a conducting enclosure as the inductance and Q of the coils will be significantly altered by the enclosure, and the coupling between the coils may provide objectionable interaction.